Propeller device



May 14, 1940. F. MERZ PROPELLER DEVICE Filed April 20, 1938 3 Sheets-Sheet 1' Fig.1

Fig. 2

INVENTOR F. MERZ May 14, 1940. F. MERZ PROPELLER DEVICE '5 Sheets-Sheet 2 Filed April 20 1938 INVENTOR I F. MERZ v 'W JATTVS.

Patented May 14, 1940 UNITED STATES PROPELLER DEVICE Francesco Mei-z, Turin, Italy Application April 20, 1938, Serial No. 203,218

In Italy April 22, 1987 8 Claims.

This invention relates to a fluid-operated piston device having its piston connected with a force transmitting element by means of a lateral arm on the piston projecting through a longitudinal slot in the cylinder, this slot being sealed by a longitudinal ribbon which is displaced as necessary by movement of the arm and piston along the cylinder.

An object of this invention is to provide an improved fluid-pressure-operated piston device of this kind, whereby greater pressures and speeds can be achieved than with the known devices, so that the device can be successfully employed as a catapult for the launching of aeroplanes.

Another object of this invention is to provide a fluid-operated piston device of the kind referred to, in which the arm is in the form of a longitudinal web and the piston and web have corresponding surfaces which define closely a smoothlycurved displacement path for the ribbon throughout substantially the whole of its displaced length. The shaping of the corresponding piston and web surfaces will be such that no injurious stresses will be set up on the strip during its displacement.

A further object of this invention is to provide a fluid-operated piston device, wherein the cylinders are in the form of a block having a plurality of bores, for example, three, each containing a piston connected to a common force transmitting element which is guided for movement along the outside of the block.

A further object of this invention is to provide a fluid-operated piston device, wherein the ribbon is preferably crescent-shaped in cross-section, the larger curve having the same radius as the cylinder wall, while the smaller curve will fit into a correspondingly curved groove containing the longitudinal slot through which the piston arm projects. I

The accompanying drawings show by way of example some constructions of the object of this invention.

Figure 1 is a partial longitudinal section showing a propeller device with the force transmitting element or carriage; Figure 2 is a side view thereof; Figure 3 is a cross sectional view of the threebore device and Figure 4 shows on an enlarged scale the ribbon on its seat. Figure 5 shows on an enlarged scale an end of the propeller device. Figure 6 is a cross sectional view of the brake.

' Figures 7, 7a and 8 are an elevation partly in secstretched at their ends by means of tensioning returning the catapult carriage to its launching position.

Referring to Figures 1 to 4, the propeller consists of a cylindrical body made up of sections I, l' in which longitudinal parallel bores 2 5 are formed. Slits 3 (Fig. 4) are formed along the generatrices of the cylinder at the minimum thickness between the bores and outer wall, and the edges of said slits are tapered to form a seat 4 for the ribbon 5. The ribbons may be of various-10 forms; however, the crescent-shaped section shown in Figure 4 is preferred for obvious con structional and resistance reasons, further because in closing the slit it completes the circular cross-section of the bore.

The tubular pistons 6 and 6' are connected together by means of a central tubular member 8 closed at its ends by covers I and I having openings through which the ribbon 5 extends. The tubular member 8 is integral with an outer longitudinal member 9 having-substantially the same overall length as the pistons and comprising a longitudinal web It merging centrally into the tubular member 8. The edge of said web is of parabolic profile and extends parallel to the similarly parabolic profile of the pistons. The distance between said edge and the pistons is slightly greater than the thickness of ribbon 5, thereby providing a guide for curving the ribbon and guiding it through the tubular member 8 on passage of the pistons. In this manner, the ribbon is lifted from its seat on the short length between the piston heads in order to clear the passage of the central portion of web l0 through the slot 3. The lateral arms are connected together by means of rings II and II sliding on the cylinder I. Pull rods l3 are journalled at I2 to the central portion of the lateral arms and are fixed to the forks l4 on the carrier IS. The torque, due to the lack of parallelism between the pistons and pull rods, is absorbed by the cylinder through the lateral arms and the rings II. The pull rods l3 act as a universal joint for making up for any possible lack of parallelism between the cylinder and guides of the carriage. The cylinder 4 sections rest on the supports l6 and are connected together by means of bushes ll.

At. the propeller device heads (Figure 5) the bores 2 communicate with the conduits I8 having attached to their flanges the fluid inlet and outlet valve casing. The plugs l9 and cover 20 are fitted to the heads after having introduced the pistons into the cylinder. The ribbons 5 are devices constituted by the forks II with screwthreaded shank and springs 22.

The use of the propeller device as a catapult necessitates the provision at both headsof members capable of launching the carriage, braking the same at the stroke end and, finally, returning it to their initial position.

A set of valves 23 is provided in the starting head in the cylinder I, Figures 7 and 8, said set comprising an inlet and outlet valve 24 and an adjusting valve 25. The valve 24 is actuated by the piston 25 in both directions, i. e. from right to left for the supply, the piston 26 receiving pressure air through the hand-operated valve 21, while for left to r ght movement for thedischarge the piston 26 receives air from the valve 23 operated by the cam 29 on the shaft 3|. The adjusting valve 25 is actuated by the rack 30 by means of a gear on the shaft 3|, which receives motion by means of a sprocket from the shaft 32 parallel to the guides 33 on which the carriage l moves. A groove 34 is formed in the shaft 32 and engages the end of the arm 35 fixed to the carriage in such manner that the movement of the carriage along the guides rotates the shaft 32, gradually opening the adjusting valve.

Brakes 36 are provided on both sides of the propeller device for the purpose of braking the carriage at the end of the strokes. As shown in Fig. 6, each brake is composed of two sheet metal members 31 fixed to the carriage and adapted to be clamped between the jaws 38 pressed by the resilient chambers 39 which receive compressed air from the tubes 40. Between the jaws 33 a third sheet metal member 4| is arranged either stationarily or capable of sliding on a short length, which acts as a brake on the inner walls of the sheet metal members 31. The resilient air chambers 39, that may be subdivided into a number of sections have, as compared with the known piston and lever brakes, the advantage of uniformly distributing pressure over the whole braking surface Air delivery to the brakes is controlled by the cock 2, actuated either by hand or by the piston '43. The cock ll and piston 45 actuated by the valve 46 supplies or discharges air into or out of the brakes oi the incomin head.

Pressure air or gas is fed to the set of valves 23 through the conduit 48, while discharge takes place through the outlet 49. Air for the brakes and other controls is supplied by the reduction valve 50. The valves 21, 28, I6, 41 etc. are of the known type in which air flows in or is discharged to the outside according as to whether the operating lever is pressed or released. It will be obvious that the operating valves may be grouped to form one unit.

The incoming head, shown in Figures 9 and 10, has a number of parts similar to those of the above described starting head, which are referred to by the same numerals with the addition of the index.

The inlet and outlet valve 24' may be operated not only by the piston 26' but also by a further piston 5|, hydraulically connected through the pipe 52 to the piston 53, of which the rod 54 is actuated by the sheet metal member ll of the brake 35 through the interposition of the pin and slot joint 55. The adjusting valve 25' is controlled by the piston 56 actuated by the valve 51, of which the driving cam 58 is co-axial to the cam 28' which drives the valve 28' which is further operated by a piston 59. The valve 51 also controls the piston 23' to bring the valve 24' into the discharge position.

The device shown in Figure 11 essentially comprises an endless chain ll moved by the motorreducer unit 6 I. A link of the chain has attached thereto the lever 62 which, on actuation of the motor, is lifted from the guide 83 and brought within the path of the projection 54 of the carriage l5, pushing the latter to its launching position.

To launch an aircraft or a projectile fixed to the carriage, the procedure is as follows. By depressing the lever of the valve 21, the valve 2| closes the outlet 49 and opens the inlet 48, so that compressed air 'flowing through the adjusting valve 25 which is in its minimum opening position. reaches through the conduit It the bores 2 in the propeller. At the same time, air is admitted to the piston 43 which acts on the cock 142 discharging the brakes 36 and releasing the carriage; which is started and effects launching. Pressure on the pistons remains constant, for the shaft 32 by rotating in the direction denoted by the arrow, Figure 'la, gradually opens the adjusting valve 25. At a determined point on the path of the carriage, the cam 29 actuates the valve 23 which closes the inlet and discharges the air admitted into the propeller device. Directly thereafter, the cam 29' at the incoming end actuates the valve 23' closing the outlet 49' and opens the braking air inlet from the tube 48' so that air flows in through the open valve 25' and presses on the pistons 6' of the movable unit. The sheet metal members 31 of the carriage reach within the tightened brakes 33' and the carriage is arrested under the combined action of the two braking means.

The thrust of the braking air now draws back the carriage, and the sheet metal member 55 of the brake 36' which is carried along in this backward movement actuates by means of the hydraulic transmission between the pistons 53 and 5i the valve 24', whereby the braking air inlet is closed and the braking air outlet is opened. The carriage is blocked.

Re-launching of the carriage from the incoming end to the starting end is effected by means of a device provided at the latter end. By depressing the lever of the valve 46 the cook 44 is actuated by means of the piston 45 and discharges the brakes 36', at the same time air pushes the piston 56 of the valve 23' to its minimum opening position (Fig. 9). This valve at the incoming end damps the re-launching speed of the empty carriage. By successively depressing the valve 41, which acts on the piston 53 the valve 28 is actuated which supplies air to the piston 26' of the valve 24', the latter re-closing the outlet 49 and admitting air for re-launching through 48. During this movement the hydraulic transmission 5l-53 resumes its position for launching.

The carriage having thus started its return stroke and attained the desired speed, the cam 58 on the shaft 32 depresses the valve 51, which supplies air to the left of the piston 55 opening the valve 25', and to the right of the piston 26' whereby the inlet re-closes and discharge takes place. The carriage moves further by virtue of its kinetic energy and is stopped at the starting end by the closed brakes 30. I

As the brakes cannot be adjusted for stopping the carriage exactly at the end of its stroke, the already described sprocket device now comes into action.

The cams 29, 29' and 58 should act on their respective valves for one direction of rotation only of the shaft 32, for which purpose they are provided with a snap device shown in Figure 7a.

By arranging the launching and braking means symmetrically at both heads, the catapult can launch in both directions though it has one propeller only.

What I claim is:

1. A propeller device, comprising a plurality of bores, each having a longitudinal slit formed along a generatrix, pistons movable in said bores, ribbons for closing said slits, a carriage, connecting means between the pistons and carriage, guiding means on said connecting means for shifting said ribbons from said slits and permitting the passage of said connecting .means through the slits, and means for admitting and discharging a pressure fluid into and out of said cylinders for reciprocating said carriage along said cylinders and braking it at the end of its strokes.

2. A propeller device, comprising a cylindrical body having a plurality of longitudinal bores and a plurality of longitudinal slits formed between the bores and outer walls of said body, ribbons for closing said slits, pistons movable in said bores, webs connected to said pistons and projecting outwards through said slits, a carriage connected to said Webs, guiding means between said pistons and said webs for shifting said ribbons from said slits and permitting the passage of said webs through the slits, and means for admitting and discharging a pressure fluid into and out of said bores for reciprocating said carriage along said body and braking the same at the end of its stroke.

3. A propeller device comprising a cylindrical body having a plurality of longitudinal bores circularly positioned around the axis of said cylindrical body, in such manner that a fluid pressure on the side walls of the bores is balanced and a plurality of slits formed between the bores and outer walls, ribbons for closing said slits, pistons movable in said bores, webs fixed to said pistons and projecting outwards through said slits, a carriage connected to said webs, guiding means between said pistons and said webs for shifting said ribbons from said slits and permitting the passage of said webs through the slits, and means for admitting and discharging a pressure fluid into and out of said bores for timely reciprocating said carriage along said body and braking it at the end of its strokes.

4. A propeller device comprising a plurality of cylinders, each having a longitudinal slit formed along a generatrix, pistons movable in said bores, ribbons of crescent-shaped section for closing said slits, said ribbons completing the circular section of the bore of saidcylinders, a carriage, connecting means between the pistons and carriage, guiding means on said, connecting means for shifting said ribbons from said slits and permitting the passage of said connecting means through the slits, and means for admitting and discharging a pressure fluid into and out of said cylinders for timely reciprocating said carriage on said bore walls is balanced and a plurality of slits formed between the bores and the outer walls, ribbons of crescent-shaped section for closing said slits, said ribbons completing the circular section of the bores of said cylindrical body, a carriage connected to said webs, guiding means between said pisons and said webs for shifting said ribbons from said slits and permitting the passage of said web through the slits, and means for admitting and discharging a pressure fluidinto and out of said bores for timely reciprocating said carriage along said body andbraking the same at the end of its strokes.

6. A propeller device comprising a cylindrical body having a plurality of longitudinal bores circularly positioned around the axis of said cylindrical body in such manner that a fluid pressure on said bore walls is balanced and a plurality of slits formed between the bores and the outer walls, ribbons of crescent-shaped section for closing said slits, said ribbons completing the circular section of the bores of said cylindrical body, webs connected to said pistons through said slits, a'carriage connected to said webs, guiding means between said pistons and said webs for shifting said ribbons from said slits thereby permitting the passage of said webs through the slits, inlet and outlet valves at both ends of said cylindrical body for admitting and discharging a pressure fluid into and out of said bores thereby pushing and braking the said carriage in either direction, and means controlled by said carriage on its motion for actuating said valves.

7. A propeller device comprising a cylindrical body having a plurality of longitudinal bores circularly positioned around the axis oi. said cylin drical body in such manner that a fluid pressure on said bore walls is balanced and a plurality of slits formed between the bores and the outer walls, ribbons of crescent-shaped section for closing said slits, said ribbons completing the circular section of the bores of said cylindrical body, webs connected to said pistons through said slits, a carriage connected to said webs, guiding means between said pistons and said webs for shifting said ribbons from said slits thereby permitting the passage of said webs through the slits, inlet and outlet valves at both ends of said cylindrical body for admitting and discharging a pressure fluid into and out of said bores thereby pushing and braking the said carriage in either direction, means controlled by said carriage on its motion for actuating said valves, and cheek brakes and fluid controlled means for releasing and braking the carriage after launching, said brakes being adapted to move over a short length with said carriage.

8. A propeller device as claimed in claim 7 comprising a sprocket mechanism for returning said carriage to its starting position.

' FRANCESCO MERZ. 

